The present invention relates to upgrading a residua feedstock using a short vapor contact time thermal process unit comprised of a horizontal moving bed of fluidized hot particles.
In a typical refinery, crude oils are subjected to atmospheric distillation to separate lighter materials such as gas oils, kerosenes, gasolines, straight run naphtha, etc. from the heavier materials. The residue from the atmospheric distillation step is then distilled at a pressure below atmospheric pressure. This later distillation step produces a vacuum gas oil distillate and a vacuum reduced residual oil that often contains relatively high levels of asphaltene molecules. These asphaltene molecules usually contain most of the Conradson Carbon residue and metal components of the resid. They also contain relatively high levels of heteroatoms, such as sulfur and nitrogen. Such feeds have low commercial value, primarily because they cannot be directly used as a fuel oil because of environmental regulations. They also have little value as feedstocks for refinery processes, such as fluid catalytic cracking, because they produce excessive amounts of gas and coke and their high metals content causes catalyst deactivation. Thus, a need exists in petroleum refining for a process for upgrading residual feeds to more valuable cleaner and lighter feeds.
There are a number of techniques used for recovering the lighter components from various petroleum residual feeds that contain high concentrations of alphaltenes. Many such processes involve separation, via extraction, of the lighter components with a deasphalting solvent such as propane, and thereafter separating and recovering the lighter components from the solvent. Other processes may use solvents that include lower alkanes, alkenes, and their halogenated derivatives, and even carbon dioxide and ammonia under certain circumstances. These processes use conventional physical separation techniques, with little or no significant chemical reactions occurring.
There is nevertheless a continuing need in the art for an upgrading and conversion process that yields higher amounts of liquid products. There is also a need in the art for a conversion process that can upgrade an asphalt-containing residual feedstock without using a solvent, while increasing liquid product yields and without causing an increase in dry gas and coke yields.